SureFil SDRflow® set up as a standard for bulk-fill flowable as easy to use and excellent adaption due to its lower viscosity, lower curing stress and high depth of cure. However, it seems highly desirable if it can be further manipulated by the clinicians although the low viscosity make possible to achieve the best adaption, which is critical to minimize the failure of the bulk restoration. Therefore, in order to improve the SureFil SDRflow® while carry its signature feature of self-leveling, a possible phase change from lower viscosity to higher viscosity become a new twist. It is expected that this would be able to effectively balance between adaptation and manipulation.
A flowable composite should be able to undergo a rheological phase change from low viscosity to a firm paste upon a paste/paste mixing. Several approaches were proposed based on either chemistry and/or technology. If a chemistry could allow a selective cure for part of formulated material to building up its texture (viscosity) in given time, it should be possible to develop such a viscosity-increasable flowable that should delivery some feature we would like. For instance, a chemical approach can be based on a sequential curing mechanism, from which distinguished chain growth and network-formation are involved in. Consequently the initial paste offer lower viscosity for achieving good adaptation and then first curing mechanist is triggered for viscosity building-up but would not cause unnecessary cross-linking. Finally cross-linking is kicked in by light irradiation for strengthening the performance.